package com.company;

import java.util.Scanner;

public class Main25 {
    public static void main(String[] args) {
        Scanner sr=new Scanner(System.in);
        System.out.println("请输入一个数返回它的阶层");
        int a=sr.nextInt();
        int s=1;
        for (int i=1;i<=a;i++){
            s*=i;
        }
        System.out.println(s);

    }
}
